Continuation of the current research program dealing with a) reproduction biology and b) development. a) We propose to investigate further the now well recognized inhibitory effect of superagonist analogs of LRF; We plan to elucidate the observation of a direct effect of the superagonist at the level of the ovary as reported in our progress report. We also propose to characterize the several peptides of ovarian origin (gonadostatins) observed here to inhibit LRF-induced secretion of the gonadotropins LF and FSH. Clinical studies with LRF-superagonists and antagonists are to be pursued. b) We propose to investigate further newly acquired hypothalamic tissue for the presence of growth hormone releasing factor. Efforts will also be devoted to the development of new methodology of improved sensitivity for the characterization of biologically active peptides.